Asbestos drier felt



Patented Aug. 9, 1927.

u i n EDUARD v.- ASTEN, or EUPEN, BELGIUM.

ASBESTOS DRIER FELT.

No drawing.

The known asbestos drier felts either consist of fabrics com osed of a lower fabric layer of cotton an an upper fabric layer of asbestos, or they are made up throughout their entire thickness of threads having a core of cotton or wool yarn densely surrounded by asbestos. I

These felts, when used as drier felts on paper and paste-board machines, still pos sess a number of drawbacks which render their use as drier felts diflicult in spite of their advantageous'absorptive and heat-resistive properties. The asbestos threads always have. a very bristly structure. The

surface of a fabric of asbestos threads is therefore rough and not at all uniform and the short crystals of asbestos may easily loosen and separate from the fabric surface and adhere to the paper to which the surface is applied. The known asbestos drier felts are, moreover, of a comparatively great thickness because they mostly consist of a plurality of superimposed fabric layers.

esides, they are soft and, owing to the constant running of the felts in a stretched con dition over the cylinders of the paper machine, they are com ressed and become thin. This compression 0 the felt and the consequent reduction of its thickness entail a 3% lengthening of the entire felt inasmuch as the warp threads are much more stretched out in the compressed fabric than in the thick fresh fabric in which they extend along undulatory lines traversing the fabric from one surface to the other. Therefore, when the felts have lengthened after some time of use on the paper machine, they must be shortened by cutting a piece out of them and sewi g the ends together anew. This so manipul tio requires always a disadvantageous stop ing of the paper machine. Besides, the ends of the felt which are sewn one upon the other form a thickened portion in the felt which is disturbant.

Now,'the invention has for its object to provide an asbestos drier felt which does no longer possess the aforesaid disadvantages.

According to the invention the felts are manufactured and delivered as endless belts.

The ends of the completed fabric are not sewn one on the other, but the terminals of the threads of the fabric are spliced into one another. Such a connection of the ends of the cloth by splicing is'wholly invisible,

it does not form a thickened portion and does not differ any more from the normal Application filed rebruarye, 1926. Serial m. 86,576.

weave of the felt. In carrying out the operation of splicing the warp threads of one felt end are drawn into the other end and spliced therein in a position which is in accordance with the'weave of the felt. The endless felt thus formed is then subjected to a treatment tending to take' the stretch out of it. To this end, the endless felt is passed over rolls and stretched to the exact length which it should finally have for being placed on the paper machine. At the same time it is subjected to the action of pressure rolls. The felt is thereby stretched so much that a further lengthening of the same on the paper machine cannot take place. According to the kind of felt, its asbestos side or the whole felt is besides impregnated with a size or the like which prevents the asbestos fibres from loosening from the surface. The. surface of the felt to be applied a to the paper is at the same time calendered by the pressure rolls and made entirely smooth. 1

The felt according to the invention there- 'fore has a smooth surface which does not felt in the desired length and-width. taking the stretch out of the felt by stretching it and subjecting it to pressure, at the same time calendering the surface to be applied to the paper and treating it with a size for making the surface smooth.

2. The process of manufacturing asbestos drier felts which consists in weaving the felt in the desired length and width, connecting the ends of the fabric by splicingso as to form an endless belt, taking the stretch out of the felt by stretching it and subjecting it to pressure, at the same time calendering the surface to be. applied to the paper and treating it with a' mm for making the surface smooth.

In testimony whereof I have signed my name to this specification.

EDUARD v. ASTEN. 

